Alternating-current-motor system.



C. S. BRADLEY.

ALTER-RATING GURRENT MOTOR SYSTEM.

APPLIUATION TILED MAY'Z, 190B.

91 0,638. Patented Jan. 26, 1909.

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Www55555 INVENTUR EHARLESS BRADLELi.

UNITED STATES PATENT OFFICE.

OHARLEQ 3 BRADLEY, OF NEW YORK, N. Y 'ASS IGNOB 'l-Q GENERAL ELEGTRIUGOMPANY,A

GDRPORATION on NEW roe-1;.

ALTEBNATHIG-OUEREHT-KO'IOR SYST M.

flpeciflcation ofLetten Patent.

Patented mi. 2c, 1909.

Application nae m 1, 1900. Serial No; new.

To all whom it may concern:

Be it known that 1, CHARLES S. BRADLEY, a citizen of the United States,residing at New York, in the county of New York, State of New York, haveinvented certain new and useful Improvements in alternating-Ourrent-Motor Systems, of which the following is a. specification.

My invention relates to the system described in my former patent, No.615,954, dated Dccember'13, 1898. In that patent I describe a method ofoperating induction motors at varying speeds, consisting of an inductionmotorenerator, the secondary of which supplies 0 motors, in combinationwith variable condensers in circuit with the secondary. As explaiiied inthat patent, by varying the amount of the condensers in circuit thespeed of the secondary member of the motor-generator and the seed of themotors may be varied; the spec of the m0- tor-generat'or falling as themotor-speed rises, and vice versa. At startin that is, when the motorsare at rest and t e motor; generator is at its maximum-speed and theequency of tile currentv in its secondar a mm1mum, the.maximum capacityshould be ncluded in the circuit. After the motors have started bygradually decreasing the capacity in e' circuit the speed of the moto=generator is decreased and the motorspeed' increased.

By my present invention I control the capacity in circuit with thesecondary of the motoripenerator automatically by means of a spec-responsive device, for instance, as a centrifugal governor mechanicallyconnected to the motor-generator. This automatic device is arranged to.maintain the roper cacity in circuit for all speeds of t emotorgenerator. en, By providing additional manually-controlled meansfor adjusting the impedance of the circuit, the speed may beprogressively controlled; for instance, if by he manual ad ustinQmeansthe capacity is made a little eater than the roper amount for that speethe speed of e motor-generator rises and the speed of the motorsf He;and this increase of speed of the motor-genorator furtherincreases'tli'e capacityof the circuit by means of the automaticcontrollmg'device, so that progressive s ted-variatioiiis obtained. On t'e other and, if by means of; the manual controlling means the capacityis'made a little less than the proper plied to amount for the speed atwhich the machines are operating, the speed of the motor-generator fallsand that of the motors rises, and this speed variation of the automaticdevice further decreases the capacity of thee stem. In this manner, bysimply shifting t 0 adjiisting means in one direction or the other, aregressive semi-automatic speed-variation is obtained, depending in rateon the amount of movement 0 the manualad'usting means. Eflicientelectric braking may 0 obtained in this manner by shifting the manualadjusting means so as to increase the capacity in the circuit, sincethis produces an increase in speed of the motor generator and a tendencto decrease in s eed in the motors, whic consequently ac as generatorsto return power to the line.

My invention will best be understood by reference to the accompanyingdrawing, in which-- Figure 1 shows diagrammatically asystem of motorcontrol arranged in accordance with my invention and Fig. 2 shows amodificatlon of themanual adjusting means. Iii the drawings, A-represents the primary member of an induction'motor-generator of thetype-described i i-my former'patent.

A represents the secondary member, which is shownrotatable, and providedwith collector r' is through which current is supthe induction motors B,B.

G G re resent condensers connected in parallel wit the'inotors andcontrolled by the switches- D D, which are arranged to out variableportions of the condensers out of circuit, so as to varyqtheir effectivecapacity.

E represents acentrifugal device mounted on the shaft of the generatorand controlling the switches D by means of the lever an connecting-rodG. This automatic device is adjusted so as to maintain the re ercapacity in the secondary circuit 0 t e motorgenerator for all speeds.

O 0 represent auxiliary condensers or other impedance devices inparallel with the main condensers C G and controlled b the hand-operatedswitch H. By meanso this switch the capacity of the secondary circuit ofthe motor-generator may be adjusted, and by increasing or decreasing thecapacity, the speed of the motor-generator is increased or the switchmember H in one direction or the other, a progressive variation of speedma be obtained. The switches D and centrii ugal member E are shown instarting position, at which time the speed of the motorgenerator is atits maximum, and the speed of the motors at a minimum. As the motorsspeed up and the motor-generator speed falls, the centrifugal weights ofthe device E are drawn inward by the spring, shifting rod G toward theright, and cutting out portions of the condensers.

Instead of employing auxiliary condensers or other impedance devices forthe manual adjustment, means may be provided for acting directly on theconnections between the centrifugal device and the switches. Such anarrangement is shown in Fig. 2, in which the hand-contrclied link I isinserted between the lever F and rod G, so as to affect the action ofthe centrifugal device on the switch I).

The link I is slotted at its lower end and guided by a pin J enteringthe slot. At its u per end the link I is llVOtGd to a handle K: whichitself is pivoted at k. The link I carries near its center a sleeve 11surrounding the link L, which is thus movable at rightangles to the linkI. The movement of the hnk I is vertical as viewed in Fig. 2, and isproduced by an upward or downward movement of the handle K. The link Lis provided at its end with pins enga g the members F and G,respectively. 'li gslots in these two members engaged by the pins at theends of link L are at an angle to each other, so that as the link I ismoved up and down, carrying link L with it, the members F and G arebrought nearer together, or are moved farther away from each other.Thus, the operation of the centrifugal device E on the aiivitlcgh D ismodified by shifting the han- Obviously, many other arran ements ofmanual adiustment me be em oyed, and consequent y I do not esire to 'mitmyself to the particular construction and arran ement oedparts hereshown, but aim in t e a pend claims to cover all modifications w liichare within the scope of my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is:

1. In combination, an induction motorenerator, an induction motorsupplied from t e secondary of said motor-generator, condensers incircuit with said secondary and automatic means for varying the 084M225of said circuit with variation in the sp of said machines. 1

2.. In combination, an induction motornerator, an induction motorsupplied from t e seconds. of said motor-generator, condensers incircuit with said secondary, and

speed-responsive means mechanically connected to one of said machinesand controlling said condensers.

3. In combination, an induction motorgenerator, an induction motorsupplied from the secondary of said motor-generator, condensers incircuit with said secondary, a switch adapted to cut variable portionsof said condensers out of circuit, and automatic means for actuatin saidswitch upon a variation of speed of sa1 machines.

4. In combination, an induction motorgenerator, an induction motorsupplied from the secondary of said motor-generator, condensers incircuit with said secondary, a switch adapted to out variable portionsof said condensers out of circuit, speed-responsive means mechanicallyconnected to one of said machines, and operative connections betweensaid means and said switch.

5. In combination, an induction motorgenerator, an induction motorsupplied from the secondary of said motor-generator, condensers incircuit with said secondary, a centrifugal device connected to one ofsaid machines, and means controlled by said device for cutting variableportions of said condensers out of circuit.

6. In combination, an induction motorgenerator, an induction motorsupplied from the secondary of said motor-generator, condensers incircuit with said secondary, a cantrifugal device connected to one ofsaid machines, a switch adapted to cut variable poroperative connectionsbetween said switch and said centrifugal device. 7. In combination, aninduction motorgenerator, an induction motor supplied 'from thesecondary of said motorenerator, condensers in circuit with saidsecondary, a speed-responsive device mechanically-connected to saidmotorenerator, a switch in circuit with said con ensers, and operativeconnections between said switch and said device.

8. In combination, an induction motorenerator, an induction motorsupplied from t e secondary of said motor-generator, condensers incircuit with said secondary, automatic means forvarying the capacit ofsaid circuit with variation in the spec of said machines, andmanually-controlled means for adjusting the effect of said automaticmeans.

9. In combination, an induction motorfinerator, an inductionlmotorsupplied from circuit.

1D. In combination, an induction motorgeneratcr, an induction motorsupplied with current from the secondary of said motor-generator,condensers in circuit with said secondary, speed-responsive meansmechanicallytions of said condensers out of circuit, and

e secondary of saidfinotor-generator, conconnected to one of saidmachines and controlling said condensers, and manually-controlled meansfor adjusting the amount of capacity in said circuit.

11. In combination, an induction motorgenerator, an induction motorsupplied with current from the secondary of said motor-generator,condensers in circuit with said secondary, a switch adapted to cutvariable portions of said condensers out of circuit, automatic means foractuating said switch u on a variation of speed of said machines, anmanuallyoperated means for adjusting the capacity of said circuit:

12. In combination, an induction motorgenerator, an induction motorsupplied from the secondary of said motor-generator, condensers incircuit with said secondary, a speedresponsive device mechanicallyconnected to said motor-generator, a switch in circuit with saidcondensers, operative connections between said switch and said device,and manually controlled means for adjusting the amount of capacity insaid circuit.

13. In combination, an induction motorgenerator, an induction motorsupplied from the secondary of said motor-generator, condensers incircuit with said secondary, automatic means for varying the capacity ofsaid circuit with variation in the speed of said machines, andmanually-controlled means for adjusting the impedance of said circuit.

14. In combination, an induction motorgenerator, an induction motorsupplied with current from the secondary of said motor-generator,condensers in circuit with said secondary, speed-responsive meansmechanically connected to one of said machines and controlling saidcondensers, and manually-controlled means ior adjusting the impedance ofsaid circuit.

In witness whereof, I have hereunto set my hand this fourth day of May,1906.

CHARLES S. BRADLEY.

Witnesses:

BENJAMIN B. HULL, MARGARET E. WOOLLEY.

